1. Technical Field
The present disclosure relates to a surface light source device and a liquid crystal display having the same, and more particularly, to a surface light source device and a liquid crystal display having the same using a field emission.
2. Discussion of the Related Art
A flat panel display apparatus, such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED), has been developed in place of a conventional display such as a cathode ray tube (CRT).
A liquid crystal display comprises an LCD panel having a TFT substrate and a color filter substrate, and liquid crystal disposed therebetween. Since the LCD panel does not emit light by itself, the LCD may comprise a backlight unit disposed behind the TFT substrate. The transmittance of the light from the backlight unit is adjusted according to an alignment of liquid crystal. The LCD panel and the backlight unit are accommodated in a chassis. The LCD may further comprise a circuit board and a driving chip to drive the LCD panel.
Light sources of a backlight unit include a Cold Cathode Fluorescent Lamp (CCFL), an External Electrode Fluorescent Lamp (EEFL), and a Flat Fluorescent lamp (FFL). These light sources use a plasma principle, and a discharging gas such as, for example, mercury (Hg), neon (Ne), and argon (Ar) is sealed in the lamp. When a high voltage is applied to an electrode of a lamp, an electron is emitted by an electric field from the electrode. The emitted electron excites, for example, mercury (Hg), thereby generating ultraviolet rays. Generated- ultraviolet rays are emitted outside and are converted into a visible ray by a fluorescent layer.
Mercury has desired efficiency, but due to environmental concerns associated with mercury, a light source not using mercury has been desired.